Browsing by Author "Ergun S."

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Effects of geometric parameters on failure behavior in joined-rivet and single lap laminated composite plate under bending moment
    (2011) Ergun S.; Karakaya Ş.; Tarakçilar A.R.; Ergun E.
    In this study, failure behavior of single lap composite plate fixed by means of both rivets and adhesive bonding was investigated using three-point bending test. Rivet connections were made on specimens at different geometrical intervals. Force-displacement graph were drawn. The composites used were made of glass epoxy materials with four plies and 0° layer angle. An FM73 film layered binder was used for binding process, whereas riveting was done with a 5 mm diameter dome shaped rivets. The bending test model was performed using Abaqus 6.9.1, finite element analysis software. After the three-point bending tests, the failure behavior obtained experimentally was compared with that obtained with numerical analysis. The failure behavior obtained experimentally was compared with that obtained with numerical analysis. In addition, two different failure criteria (Tsai-Wu and Tsai-Hill) were used for the composite test specimens and the failures that occurred in each layer were determined. © 2011 Academic Journals.
  • No Thumbnail Available
    Item
    Exact solution and buckling configuration of nanotubes containing internal flowing fluid
    (Association for Scientific Research, 2013) Sinir B.G.; Uz F.E.; Ergun S.
    In this study, the post-divergence behaviour of nanotubes of conveying internal moving fluid with both inner and outer surface layers are analyzed in nonlinear theorical model. The governing equation has the cubic nonlinearity. The source of this nonlinearity is the surface effect and mid-plane stretching in the nanobeam theory. Exact solutions for the post buckling configurations of nanotubes with clamped-hinged with torsionally spring and hybrid boundary conditions is found. The critical flow velocity at which the nanotube is buckled is shown. The effects of various non-dimensional system parameters on the post-buckling behaviour are investigated.
  • No Thumbnail Available
    Item
    Effect of Hysteretic Models on Seismic Behavior of Existing RC Structures
    (American Society of Civil Engineers (ASCE), 2015) Ergun S.; Demir A.
    The aim of this study is to investigate the effect of hysteretic models on displacement demands of reinforced concrete (RC) structures having various irregularities and determine more proper hysteretic models for different types of RC structures. The RC structures having irregularities such as soft story and overhang were analyzed with nonlinear pushover and nonlinear time-history methods. Concrete compressive strength, stirrup amount, and the number of stories for the structures were variable parameters. Totally, 25,664 analyses were carried out. Displacement capacities and performance levels of structures were determined using nonlinear pushover analysis. Exceedance ratios of performance levels and displacements demanded from the structures of 100 severe ground motions that occurred worldwide were obtained using nonlinear time-history analysis (NTHA). In NTHA, various hysteretic models were used to define inelastic behavior of RC structures. The analyses show that the hysteretic models have a significant effect on displacement demands of RC structures. Finally, proper hysteretic models are suggested according to the type of structure and purpose of occupancy. © 2014 American Society of Civil Engineers.
  • No Thumbnail Available
    Item
    Experimental and numerical investigation of walls strengthened with fiber plaster
    (Techno-Press, 2015) Başaran H.; Demir A.; Baʇci M.; Ergun S.
    The topic of this study is to investigate behaviors of masonry walls strengthened with reinforced fiber plaster under diagonal tensile loads. Full blend brick 100×50×30 mm in dimensions were used to make masonry walls with dimensions of 400×400×100 mm. Three different samples were manufactured by plastering masonry walls with traditional style, with 3% polypropylene or with 5% steel fiber. All the samples were tested using ASTM 1391- 81 standards. The propagation of damage on samples caused by diagonal tensile load was observed and load-displacement graphs were plotted for each sample. A finite element software (ABAQUS) was used to obtain numerical values for all samples and crack patterns and load-displacement responses were obtained. Experimental and numerical results were compared. Copyright © 2015 Techno-Press, Ltd.
  • No Thumbnail Available
    Item
    Nationwide prospective audit for the evaluation of appendicitis risk prediction models in adults: Right iliac fossa treatment (RIFT) - Turkey
    (Oxford University Press, 2024) Yalcinkaya A.; Yalcinkaya A.; Balci B.; Keskin C.; Erkan I.; Yildiz A.; Kamer E.; Leventoglu S.; Caglikulekci M.; Zarbaliyev E.; Sevmis M.; Ulgen Y.; Altinel Y.; Meric S.; Akbas A.; Hacim N.A.; Vartanoglu Aktokmanyan T.; Aktimur Y.E.; Calikoglu F.; Gullu H.F.; Durma A.G.; Acar S.; Ciftci E.; Balik E.; Kulle C.B.; Ozata I.H.; Tufekci T.; Tatar C.; Sevinc M.M.; Sevik H.; Ertürk C.; Kiraz I.N.; Ozben V.; Aytac E.; Aliyeva Z.; Mutlu A.U.; Tanal M.; Celayir M.F.; Bozkurt E.; Yetkin S.G.; Ergin E.; Attaallah W.; Uprak T.K.; Omak A.; Simsek O.; Bozkurt M.A.; Kara Y.; Bozdag E.; Yirgin H.; Ozcan A.; Okkabaz N.; Ozdenkaya Y.; Haksal M.C.; Pekuz C.K.; Duru S.; Sivrikoz E.; Ozdemir Y.; Tan N.; Yarbug Karayali F.; Taghiyeva A.; Tirnova I.; Erenler Bayraktar I.; Bayraktar O.; Emsal E.Z.; Dalkilic M.I.; Yesiltas M.; Tok H.; Karakas D.O.; Pusane A.; Demirer A.I.; Sahin H.B.; Gok A.F.K.; Bozkurt H.A.; Yildirim M.; Uzunyolcu G.; Yanar H.T.; Ergun S.; Kutluk F.; Uludag S.S.; Zengin A.K.; Ozcelik M.F.; Sanli A.N.; Altuntas Y.E.; Memisoglu E.; Sari R.; Akdogan O.; Kucuk H.F.; Ozkan O.F.; Ulgur H.S.; Kirkan E.F.; Yuksekdag S.; Rencuzogullari A.; Aktas M.K.; Aba M.; Demirel A.O.; Eray I.C.; Aydogan B.; Cetinkunar S.; Yener K.; Sozutek A.; Irkorucu O.; Bayrak M.; Altintas Y.; Alabaz O.; Atasever A.; Erdogrul G.; Kupeli A.H.; Muhammedoglu B.; Kokdas S.; Kaya M.; Uysal E.; Yildirim A.C.; Zeren S.; Ekici M.F.; Algin M.C.; Kucuk G.O.; Eraslan H.; Aybar E.; Polat S.; Ceylan A.; Isik O.; Kural S.; Aktas A.; Bakar B.; Uzunoglu M.Y.; Gulcu B.; Ozturk E.; Devay A.O.; Taspinar E.; Balcin O.; Aksoy F.; Garip G.; Yalkin O.; Iflazoglu N.; Yigit D.; Kaya R.B.; Ugur M.; Kilic E.; Dedemoglu A.; Arslan R.E.; Temiz M.; Aydin C.; Demirli Atici S.; Kaya T.; Ozturk S.; Calik B.; Kilinc G.; Acar T.; Acar N.; Cengiz F.; Ureyen O.; Tan S.; Ilhan E.; Turk Y.; Durak A.T.; Yilmaz M.; Mercan M.; Atci R.; Sokmen S.; Bisgin T.; Egeli T.; Yildirim Y.; Safak T.; Celik K.; Yilmaz E.M.; Kirnap M.; Demirkiran A.E.; Sekerci U.U.; Karacan E.; Bilgic E.; Ozmen M.M.; Guldogan C.E.; Gundogdu E.; Moran M.; Erol T.; Dincer H.A.; Kirimtay B.; Yilmaz S.; Cennet O.; Yildiz A.; Sahin C.; Akyol C.; Koc M.A.; Ersoz S.; Turhan A.; Konca C.; Tezcaner T.; Erkent M.; Aydin O.; Avci T.; Altiner S.; Osmanov I.; Emral A.C.; Cetinkaya G.; Lapsekili E.; Sakca M.; Cimen S.; Ozen D.; Kozan E.B.; Dogan L.; Haberal E.; Kayhan O.; Aksel B.; Karabacak H.; Azili C.; Yazici F.; Apaydin M.; Kaya I.O.; Cetinkaya E.; Akin T.; Gunes G.; Turap H.; Aslan D.; Demirbag A.E.; Bolukbasi B.; Karaca B.E.; Ozturk E.; Ozeller E.; Kayacan G.S.; Borcek A.O.; Ece I.; Yormaz S.; Colak B.; Calisir A.; Sahin M.; Arslan K.; Hasirci I.; Ulutas M.E.; Metin S.H.; Gultekin F.A.; Ozkan Z.; Ilhan O.; Gundogdu T.; Liman R.K.; Kanat B.H.; Aydin A.; Sungurtekin U.; Ozgen U.; Aykota M.R.; Altintoprak F.; Gonullu E.; Cakmak G.; Dulger U.C.; Mantoglu B.; Demir H.; Akin E.; Eroz E.; Nazli O.; Dere O.; Dadasoglu M.A.; Kara E.; Tutcu S.; Solak I.; Gencer I.; Dalkiran A.; Sevinc B.; Karahan O.; Damburaci N.; Sari E.; Akay T.; Calta A.F.; Ozdemir A.; Ohri N.; Ermis I.; Bozbiyik O.; Ozdemir M.; Goktepe B.; Demir B.; Kilincarslan O.; Gunduz U.R.; Olcum M.; Dincer O.I.; Cakir R.C.; Dinc B.; Sahin E.; Uludag E.; Arslan Y.; Posteki G.; Oktay A.; Tatar O.C.; Guler S.A.; Utkan N.Z.; Tayar S.; Copelci Y.; Kartal M.; Kalayci T.; Yeni M.; Buyukkasap A.C.; Vural S.; Kesicioglu T.; Aydin I.; Gulmez M.; Saracoglu C.; Topcu O.; Kurt A.; Soylu S.; Kurt B.; Serin M.; Basceken S.I.; Gundes E.; Savda M.; Balkan A.Z.A.; Yildiz M.N.; Uzunkoy A.; Karaca E.; Berkan A.; Isik A.; Yildiz Y.A.; Ergul Z.; Yasar N.F.; Badak B.; Ozen A.; Velipasaoglu M.; Ure I.
    Background: Appendicitis is the most prevalent surgical emergency. The negative appendicectomy rate and diagnostic uncertainty are important concerns. This study aimed to assess the effectiveness of current appendicitis risk prediction models in patients with acute right iliac fossa pain. Methods: A nationwide prospective observational study was conducted, including all consecutive adult patients who presented with right iliac fossa pain. Diagnostic, clinical and negative appendicectomy rate data were recorded. The Alvarado score, Appendicitis Inflammatory Response (AIR), Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) and Adult Appendicitis Score systems were calculated with collected data to classify patients into risk categories. Diagnostic value and categorization performance were evaluated, with use of risk category-based metrics including 'true positive rate' (percentage of appendicitis patients in the highest risk category), 'failure rate' (percentage of patients with appendicitis in the lowest risk category) and 'categorization resolution' (true positive rate/failure rate). Results: A total of 3358 patients from 84 centres were included. Female patients were less likely to undergo surgery than men (71.5% versus 82.5% respectively; relative risk 0.866, 95% c.i. 0.834 to 0.901, P < 0.001); with a three-fold higher negative appendicectomy rate (11.3% versus 4.1% respectively; relative risk 2.744, 95% c.i. 2.047 to 3.677, P < 0.001). Ultrasonography was utilized in 56.8% and computed tomography in 75.2% of all patients. The Adult Appendicitis Score had the best diagnostic performance for the whole population; however, only RIPASA was significant in men. All scoring systems were successful in females patients, but Adult Appendicitis Score had the highest area under the receiver operating characteristic curve value. The RIPASA and the Adult Appendicitis Score had the best categorization resolution values, complemented by their exceedingly low failure rates in both male and female patients. Alvarado and AIR had extremely high failure rates in men. Conclusion: The negative appendicectomy rate was low overall, but women had an almost three-fold higher negative appendicectomy rate despite lower likelihood to undergo surgery. The overuse of imaging tests, best exemplified by the 75.2% frequency of patients undergoing computed tomography, may lead to increased costs. Risk-scoring systems such as RIPASA and Adult Appendicitis Score appear to be superior to Alvarado and AIR. © 2024 The Author(s). Published by Oxford University Press on behalf of BJS Foundation Ltd.